In the conventional common vehicle door latch device, unlocking operations by an inside lock button, a remote control transmitter and the like are not normally completed if the outside open handle of a door is in the state of being manipulated by an opening operation, nor is it possible to open the door. Such a state is referred to as a panic state in the industry. If the door is getting into the panic state, the outside open handle is made to return to a non-operation state, then the unlocking operation is made to perform by means of the remote-control transmitter or the like again, after that, the opening operation of the door handle is performed again, so that the door is opened. That is, two unlocking operations and two door opening operations are required until the door is opened. Thus, the state, which necessitates two times of unlocking operation and two times of door-opening operation, is defined as the panic state in the present invention.
The door latch device composed of the anti-panic mechanism, which reduces complicated operation caused by occurrence of the panic state, is known (Japanese Utility Model Application Laid-Open No. 58-101949, and Japanese Patent Application Laid-Open No. 11-324451). The known anti-panic mechanism is to eliminate the second unlocking operation. Even though the first unlocking operation is not completed normally by the first door-opening operation of the outside open handle, a shifting to the unlocked state is completed when the door handle is restored to the non-operation state. Hence, when the second opening operation of the door handle is subsequently performed, it is possible to open the door even if the second unlocking operation is not performed.
Further, there is a conventionally known double action mechanism for shifting the latch device into the unlocked state when an inside open handle is subjected to the opening operation under the locked state, and for releasing the latch device when the inside open handle is subjected to the opening operation again under the unlocked state (Japanese Patent Application Laid-Open No. 2000-303731).
However, conventionally, a door latch device, which is provided with both of the double action mechanism and the anti-panic mechanism, is not developed.
This is not that this combination does not reside simply until now, but difficult combination avoids practical realization. That is, the double action mechanism is a mechanism related to the inside open handle, to the contrary, the anti-panic mechanism is a mechanism related to the outside open handle, and when combining the both simply, to become very large latch device that is not practical.